Electronic tube



June 18, 1946. w. w. EITEL ETAL 2,402,319

- ELECTRONIC TUBE v Filed June 5', 1942 2 Sheets-Sheet 1 INVENTORSWILL/AM W E/TEL BY dAc/r A. MfCL/LLOUGH THEIR ATTORNEY June 18, 1946. wEI L ET-AL 2,402,319

ELECTRONIC TUBE Filed Juhe 5, 1942 2 Sheets-Sheet 2 INVENTORS WILLIAM14/. EITEL BY (JACK A. M5 CULLOUGH THEIR ATTORNEY Patented June 18, 19462,402,319 ELECTRONIC TUBE William W. Eitel, San Bruno, and Jack A.McCullough, Millbrae, Calif., assignors to Eitel- McCullough, Inc., SanBruno, Califi, a corporation of California Application June 5, 1942,Serial No. 445,954

Our invention relates to a thermionic tube, and more particularly to arectifier.

It is among the objects of our invention to provide a rectifier tube ofsmall physical size, having an improved structure of, arrangement for,and mounting of the electrodes and leads in the en velope.

Another object is to provide a rectifier tube structure adapted forfacile assembly.

The invention possesses other objects and fea tures of advantage, someof which, with the foregoing, will be set forth in the followingdescription of our invention. It is to be understood that we do notlimit ourselves to this disclosure of species of our invention, as wemay adopt variant embodiments thereof within the scope of the claims.

Referring to the drawings:

Figure 1 is a side elevational view of a tube on approximately doublescale, embodying the improvements of our invention.

Figure 2 is a plan view of the same.

Figure 3 is a vertical sectional view on still larger scale, taken in aplane indicated by line 3-3 of Figure 2.

In terms of broad inclusion, our tube comprises an envelope enclosing acathode and plate. A lead coaxial with the plate is sealed to an end ofthe envelope; and means secured to an end cap on the plate is providedfor supporting the plate on the coaxial lead. In our preferred tube theenvelope comprises a plurality of cup-shaped sections sealed togetheralong abutting edges. Leads for the cathode are preferably sealed to thebase section, and the plate lead is preferably sealed to the bodysection.

In greater detail, and referring to the drawings, our rectifier tubecomprises a cylindrical envelope of glass or the like having a bodysection 2 and a base section 3, both cup-shaped and sealed togetheralong abutting edges at the bead 4 in a plane lying transversely of theenvelope. The base section is shorter than the body; more like a shallowdish compared to the deeper cupped body 2. Base section 3 alsopreferably has thicker walls than the body to give added strength at thebase of the tube. A tubulation for evacuating the envelope is connectedto the body section and, after exhaust, is sealed off the pump at point5. The envelope is of small physical size, say about 1% inches indiameter by about 1 /2 inches in length.

The plate or anode 6 comprises a pair of drumshaped sections, preferablyof tantalum, disposed end-to-end. Flanges 1 are integrally formed atClaims. Cl. 25027.5)

the abutting ends of the sections, and the sections are secured togetherby spot welding the flanges. These flanges thus form an annular heatradiating fin disposed about the mid-portion of the tubular plate. Ahemispherical tantalum cap 8 is secured over the upper end of the plateby depending tabs 9 welded to the plate rim. Arched recesses II in thecap between the tabs provide .vent openings.

A plate lead I2, preferably of tungsten, is disposed coaxially of theplate and projects thru the top of envelope section 2 at seal l3. Theplate supporting means preferably comprises a yokeshaped bracket M oftantalum having arms spot welded to cap 8. Both parts being of tantalumthey weld readily. It is more difiicult to weld to the tungsten however,and we preferably first spot weld a piece of nickel Hi to the bracketand then weld this to the end of lead l2. The body of nickel interposedbetween the parts alloys or fiuxes readily with both the tantalum andtungsten, providing a strong joint.

Cathode leads I! and I8 are also preferably of tungsten. They projectthrough the base section of the envelope at seals l9. Lead I1 isprovided with a reduced extension 20 of tungsten bent to projectupwardly thru the center of the plate. The other lead [8 may either be asolid rod as shown in Figure 1 or have a reduced extension 22 asillustrated in Figure 3. The lead extensions are butt welded to theenlarged portions, preferably using nickel 23 as a flux at the welds.

Cathode 24 is preferably of the filamentary type comprising a coil ofthoriated tungsten welded at the upper end to lead extension 20 and atthe lower end to a tantalum strap 26 which in turn is welded to theother lead.

The tube is fabricated by forming the envelope in two separate sectionswhich, prior to sealing together, are open at one end. The plateassembly is welded together apart from the tube, and, after lead I2 hasbeen sealed in place, plate bracket I4 is welded to the lead. Analternate procedure is to weld the plate assembly to the lead apart fromthe envelope, and then seal the lead to the glass.

The cathode leads are sealed to the separate base section, and filament24 is thereafter welded in place. Since the cathode leads project outthru the open mouth of the shallow base section, the filament may bereadily positioned and welded. After mounting the electrodes, thefilament is centered within the plate and the two envelope sections arefused together along abutting edges at seal 4.

We claim:

1. A rectifier tube comprising an envelope, a tubular plate and acathode in the envelope, an end cap on the plate, a lead sealed to theenvelope, a bracket on the cap for supporting the plate on the inner endof said lead, and leads for the cathode sealed to the envelope.

2. A rectifier tube comprising an envelope, a tubular plate and acathode in the envelope, an end cap on the plate, a lead coaxial withthe plate and sealed to the envelope, a bracket on the cap forsupporting the plate on the inner end of said lead, and leads for thecathode sealed to the envelope.

3. A rectifier tube comprising an envelope, a tubular plate and acathode in the envelope, an annular fin disposed about the plate, an endcap on the plate, a lead sealed to the envelope, a bracket on the capfor supporting the plate on the lead, and leads for the cathode sealedto the g0 envelope.

4. A rectifier tube comprising an envelope embodying a pair ofcup-shaped sections sealed together along abutting edges, a tubularplate and a cathode in the envelope, an end cap on the plate, a leadsealed to one of the envelope sections, a bracket on the cap forsupporting the plate on the inner end of said lead, and lead for theoathode sealed to the other section of the envelope.

5. A rectifier tube comprising an envelope embodying body and basesections, said sections being cup-shaped and sealed together alongabutting edges, a tubular plate and a cathode in the envelope, an endcap on the plate, a lead coaxial with the plate and sealed to the bodysection, a bracket on the cap for supporting the plate on said lead, andleads for the cathode sealed to the base section.

WILLIAM W. EITEL.

JACK A. MOCULLOUGH.

